Just Wondering: A New Moon

So, it occurred to me, when I went outside and looked up at the stars, wouldn't it be feasibly possible for the earth's gravity to catch an asteroid, but, for some reason, the asteroid was flung into orbit around the earth.

So, I was wondering... how would this affect us.

If the asteroid was big enough and close enough in orbit, could it technically not be seen from the ground as a lit object with it's own cycles and eclipses?
Other than the 'beauty' aspect.
How would a new moon affect tidal patterns?
Would its surface be explored?
How fast would it orbit?

I also realized that this could happen at ANY moment in time. Think about, a random asteroid, seemingly about to crash into earth, but, instead orbits the Earth.

Oh, and does anybody know the chances of this happening?
Say the chances of an asteroid earthbound either crashing or orbiting.

The fact that a asteroid must be traveling not too fast or not too slow to be captured by Earth's orbit is very difficult to do, without human intervention. About a asteroid reflecting sunlight is also very difficult unless it is made of the same material and texture as the Moon's. And unless it is very dense, or very heavy, won't effect any tides.

Technically it's almost completely impossible for an asteroid to become an Earth satellite since many conditions have to met to have that happen.

http://www.earthsky.org/faqpost/space/as...-accretion

So..
Basically a very small chance.
I'll keep dreaming :O

Before it gets caught in the orbit and becomes a new moon, we would get crushwd by it, its very unlikely to happen

There's been some talk of deliberately doing this for ease of mining. It would have to be extraordinarily large to be any more than a point of light, though. A few years back, an Asteroid passed very close to earth, and you could see it from the ground. I went out and watched it, it was basically just an orange point. It was visibly moving across the sky, though. If you want to know what it would be like, I would say look to Mars, because Mars has two small asteroid-like moons. They don't seem to be much to look at, though.

Speaking of stellar collisions, people estimated that when the Milky Way and Andromeda duke it out billions of years from now, assuming Earth still exists, there would be a 10% chance of us actually crashing into anything from the disturbance.